Nanoscale Effect Investigation for Effective Bulk Modulus of Particulate Polymer Nanocomposites Using Micromechanical Framework

This paper investigates the nanoscale effect on the effective bulk modulus of nanoparticle-reinforced polymer. An interface-based model is introduced in this work to study the nanoscale effects on the effective properties of heterogeneous materials. That interface model is able to capture discontinuity of mechanical fields across the surface between the nanoparticle and matrix. A generalized self-consistent scheme is then employed to determine the effective bulk modulus. It has been seen from the results that, in a certain range of limits, the influence of nanoscale effects on effective properties of heterogeneous materials is significant and needs to be taken into account. In particular, when the nanoparticle radius is smaller than 10 nm, the value of effective bulk modulus significantly increases when the characteristic size of nanofillers decreases. Besides, it is seen that the harder the inclusion, the smaller the nanoscale influence effects on the overall behaviors of composite materials. Finally, parametric studies in terms of surface strength and filler’s volume fractions are investigated and discussed, together with a comparison between the proposed model and other contributions in the literature.

The Simulation of Liquid Flow in the Pore Network Model of Nanoporous Media

The fluid–solid interaction force shows significant influence on liquid flow at nanoscale. Vast experimental observations in recent literatures have shown that Darcy's law cannot be applied to nanoporous media. In this study, the slip length and effective viscosity are adapted to characterize the nanoscale effect. First, the nanoscale effect is investigated in nanotubes through computational fluid dynamic (CFD) modeling analysis. Slip boundary condition has been studied as an important discrepancy between macroscopic flow and nanoscale liquid flow. The effect of viscosity change becomes more notable with the slip length increasing. Then, the flow equation for pore network modeling is developed to capture nanoscale effect. The results show that the apparent permeability of nanoscale systems is significantly underestimated when slip effect is neglected. The size of the pore throat determines whether the slip effect needs to be considered, and critical diameter of neglecting the slip effect for circular throat is 79.17 Ls. It is necessary to take the variation of effective viscosity into account under slip boundary condition. With the pore throat size decreasing, the nanoscale effect increases. The nanoscale effect is more sensitive to pore throat size under hydrophobic conditions than hydrophilic conditions.

Experimental Views of Tran-Bend Particle Deposition in Turbulent Flow with Nanoscale Effect

This paper presented experimental views of nano- and microaerosol distribution and deposition in turbulent tran-bend flows. These views included the particle flow measurement and particle depositions through individual bends, bifurcation bends, and those behind bends. Selected experiments were summarized and compared according to the gas flow, the bend geometry, and the particle flow properties. Based on recent studies, the influencing factors of environmental humidity, particle and surface properties, nanoparticle formation, coagulation, or evolution phenomena were discussed, and then research suggestions were given for future research and applications. It is specially mentioned that the new particle formation and nanoparticle growth affect its deposition under environmental contaminant conditions; nanoscale particle dynamics and transport have a growing trend on attracting the research and industry attentions.